Headphone



FIG. 1 is a front view of a headphone;

FIG. 2 is a rear view;

FIG. 3 is a right side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a front elevational view thereof; and,

FIG. 7 is a bottom elevational view thereof.

The broken lines form no part of the claimed design. 

CLAIM The ornamental design for a headphone, as shown and described. 